Truing jack



1942- c. K. BROB$T 2,291,687

TRUING JACK Filed Aug. 21, 1941 Patented Aug. 4, 1942 UNITED STATESPATENT OFFICE TRUING JACK Charles K. Brobst, Hamburg, Pa.

Application August 21, 1941, Serial No. 407,832

3 Claims. (Cl. 82-34) This invention relates to a truing jack for usewith the face plate of a lathe chuck, and it is a particular object ofthe invention to provide a device of this kind so constructed andassembled to eliminate displacement or derangement of the jack as aresult of the centrifugal action to which it may be subjected when theface plate is in rotation.

It is an object of the invention to provide a jack of this kind whichcan be mounted upon the face plate in desired selected position wherebythe efficacy of the jack is materially increased and particularly inconnection with precision work.

The invention consists in the details of construction and in thecombination and arrangement of the several parts of my improved truingjack whereby certain important advantages are attained, as will behereinafter more fully set forth.

In order that my invention may be the better understood, I will nowproceed to describe the same with reference to the accompanying drawing,wherein- Figure 1 is an elevational view of a face plate for a lathechuck having mounted thereon jacks constructed in accordance with anembodiment of my invention;

Figure 2 is a View in side elevation of the jack unapplied;

Figure 3 is a sectional view taken substantially on the line 3-3 ofFigure 2; and

Figure 4 is a detailed sectional View taken substantially on the line4-4 of Figure 3.

As disclosed in the accompanying drawing, F

denotes a conventional type of face plate for a lathe chuck and which isprovided with the perpendicularly related grooves or channels I withwhich are associated the required work engaging clamps 2. Between thegrooves or channels I are arranged the supplemental grooves or channels3 disposed substantially radially of the face plate, and with which areassociated the jacks A constructed in accordance with an embodiment ofmy invention.

My improved jack as herein disclosed comprises an elongated base plate 4of desired configuration and dimensions, preferably rectangular in form.One end portion of this plate 4 is provided therethrough, atsubstantially its transverse center, with an opening 5 through which isdisposed the shank 6. This shank 6, at the under side of the plate 4, isprovided with a head or enlargement I which is adapted to ride within toextend a desired distance beyond the upper or outer face of the plate 4so that a clamping nut 8 may be threaded thereon for holding the plate 4in desired selected position upon the face plate F. The plate 4 may beadjusted as desired lengthwise of its groove or channel 3, may bereversed, or may be axially adjusted about the shank 6 as preferred, toassure effective coaction with the work.

The opposite end portion of the plate 4 is provided therethrough with arelatively large opening 9 in which is tightly pressed an end portion ofa cylindrical block ID of desired dimensions. This block ll] extendsbeyond the outer or front face of the plate 4 and at a point eccentricto its axial center has disposed lengthwise therethrough an opening II.The outer portion a of this opening H is enlarged and snugly fitting insaid enlarged portion a is a sleeve l2. Normally,

one of the grooves 3. This shank 6 is of a length the bore of the sleevel2 and the inner or re.- stricted portion b of the opening II are ofsubstantially the same diameter and said sleeve 12 and the portion 1) ofthe opening II are internally threaded to allow for the adjustableengagement therethrough of the elongated and relatively heavy threadedshank l4. This shank I4, at its outer end, is provided with anenlargement or head l5 having suitable side facets 16 to permit asuitable implement to be engaged with said head to extend or retract theshank l4 with respect to the block H] as may be required in order toeffect the desired truing of the work in connection with the face plateF. It is to be stated that in practice the head or enlargement l5 hasdirect contact with the work.

In practice the face plate F rotates at a high speed and, therefore, itis essential that means be provided for effectively holding or lockingthe shank [4 in its desired position. As comprised in the presentinvention, the sleeve 12, substantially midway its ends, is providedwith a longitudinal slit l1 extending from the inner end of the sleeve12 to a point substantially midway of the sleeve. The inner end of thisslit H has in communication therewith a circumferentially disposed slitI8 extending substantially one-half way around the sleeve l2, whereby isprovided an elongated and substantially semi-circular tongue 19possessing suflicient inherent resiliency to normally coincide with thesleeve 12 proper. The block [0 is provided therethrough with a radiallydisposed opening 20 which communicates with the inner part of theenlarged portion a of the opening II, and over the inner end of whichopening 20 is disposed the tongue l9.

Threading into this opening 20 is a set screw 2| the outer end portionof which being provided with a socket 22 into which is adapted to beengaged a suitable key whereby the screw 2| may be rotated as requiredto move the screw 2| inwardly or to retract the same. It is to bepointed out that the assembly is such that the opening 20 is disposedthrough the thicker portion of the block II] to one side of the openingH so that the screw 21, in its effective and released positions, will beentirely housed within the opening 20.

When the shank I4 is to be adjusted to effect the desired truing of thework, the screw 2| is retracted or moved outwardly a distance sufiicientto allow the tongue I9 to be in its normal position so that the shank 14may be readily threaded outwardly or inwardly with respect to the blockI as may be desired. After the desired adjustment of the shank I 4 hasbeen effected, the screw 2| is moved inwardly to causethe tongue l9 totightly bind against the shank l4 and thereby effectively lock the shank[4 in its required adjustment.

From the foregoing description it is thought to be obvious that a truingjack constructed in accordance with my invention is particularly welladapted for use by reason of the convenience and facility with which itmay be assembled and operated.

I claim:

1. A truing jack for the face plate of a lathe chuck comprising a plate,means for securing the plate to the face plate, a block carried by thesecond plate and extending outwardly beyond the outer face thereof, saidblock having an opening disposed therethrough, a portion of said openingbeing enlarged, a sleeve fitted within said enlarged portion of theopening of the block, one

end portion of the sleeve being slotted to provide a tongue extendingcircumferentially and partly around the sleeve, a shank threadingthrough the sleeve and the opening of the block, the outer end of theshank to have contact with the work to be trued, and means extendingthrough the block engaging the tongue of the sleeve for forcing thetongue against the shank to lock the shank in a selected adjustedposition.

2. A truing jack for the face plate of a lathe chuck comprising a plate,means for securing the plate to the face plate, a block carried by thesecond plate and extending outwardly beyond the outer face thereof, saidblock having an opening disposed therethrough, a portion of said openingbeing enlarged, a sleeve fitted within said enlarged portion of theopening of the block,

one end portion of the sleeve being slotted to providea tongue extendingcircumferentially and partly around the sleeve, a shank threadingthrough the sleeve and the opening of the block, the outer end of theshank to have contact with the Work to be trued, and means extendingthrough the block engaging the tongue of the sleeve for forcing thetongue against the shank to lock the shank in a selected adjustedposition, the means for locking the shank including a screw threadinginto the block and contacting with the tongue of the sleeve. 1

3. A truing jack for the face plateof a lathe chuck comprising a plate,means for securing the plate to the face plate, a block carried by thesecond plate and extending outwardly beyond the outer face thereof, saidblock having an opening disposed therethrough, a sleeve fitted withinthe opening of the block, one end portion of the sleeve being slotted toprovide a tongue extending circumferentially and partly around thesleeve, a shank extending within the opening of the block and threadingthrough the sleeve, the outer end of the-shank to have contact with thework to be trued, and means ext-ending through the block engaging thetongue of the sleeve for forcing the sleeve against the shank to lockthe shank in a selected adjusted position. H

CHARLES K. BROBST.

